Burst communications via a bus bar and bus bar relay for an automated data storage library

ABSTRACT

An automated data storage library with storage shelves, data storage drive(s), a bus bar; and a robot accessor with a drive system for moving the robot accessor, an accessor communication interface, a bus bar relay configured to engage and disengage the bus bar; and a robot control configured to operate the drive system to move the robot accessor, to operate a picker, and to operate the bus bar relay to engage the bus bar when the robot accessor is stationary, to provide communication capability with a library communication interface via the bus bar relay and the bus bar when the bus bar relay engages the bus bar. Additionally, a second communication system may be provided between the robot accessor and the automated data storage library, which is operable at least when the robot accessor is moving.

FIELD OF THE INVENTION

This invention relates to automated data storage libraries and, moreparticularly, to communication with the robot accessor of the automateddata storage library.

BACKGROUND OF THE INVENTION

Automated data storage libraries provide access to data storagecartridges which are typically stored in storage shelves and accessed bya robot accessor having a picker configured to access and deliver datastorage cartridges to and from storage shelves and one or more datastorage drives. The robot accessor typically moves back and forth amongthe storage shelves and data storage drives, and positions the picker atthe desired storage shelf or data storage drive. Communication isprovided to the robot accessor, for example, as commands or signals tomake the desired moves, or as address information so that a processor ofthe robot can determine the desired moves. Additionally, a detector maybe mounted on the robot accessor or picker to read information from theshelves, markers within the library, and/or from labels on the datastorage cartridges.

Communication with the robot accessor is typically made via a flexiblecable which unwinds and winds in accordance with the movement of therobot accessor. The flexible cable has certain disadvantages includingthe possibility of breakage, difficulty in turning corners or crossingaisle intersections, and the need to replace the cable when the libraryis expanded. Other techniques include wireless radio and infraredcommunications. Radio poses security and interference risks, whileinfrared or other optical means can have interference and line-of-sightconcerns.

SUMMARY OF THE INVENTION

Automated data storage libraries, robot communication systems, andcomputer program products are provided.

In one embodiment, an automated data storage library comprises aplurality of storage shelves, at least one data storage drive, a busbar, a library communication interface configured to communicate withthe bus bar, and a robot accessor. The robot accessor comprises a pickerconfigured to access and deliver data storage cartridges to and from thestorage shelves and the data storage drive(s), a drive system configuredto move the robot accessor and to position the picker, at least suchthat the picker may be positioned to access and deliver the data storagecartridge(s), an accessor communication interface, a bus bar relayconfigured to engage and disengage the bus bar; and a robot controlconfigured to operate the drive system to move the robot accessor, tooperate the picker, to operate the bus bar relay to engage the bus barwhen the robot accessor is stationary, and to operate the accessorcommunication interface to provide communication capability with thelibrary communication interface via the bus bar relay and the bus barwhen the bus bar relay engages the bus bar.

In a further embodiment, the automated data storage library additionallycomprises a second communication system between the robot accessor andthe automated data storage library, the second communication systemoperable at least when the robot accessor is moving.

In another embodiment, the second communication system is a lowbandwidth communication system as compared to communication bandwidthbetween the accessor interface and the library communication interfacevia the bus bar relay and the bus bar.

In still another embodiment, the second communication system comprisesan optical communication system.

In a still further embodiment, the second communication system comprisesan RF communication system.

In another embodiment, the second communication system comprises aroller and bus communication system.

In still another embodiment, the second communication system comprises abrush and bus communication system.

In a further embodiment, the robot control is additionally configured tostop the robot accessor if, while the bus bar relay is disengaged,communication of the second communication system is lost for apredetermined threshold.

In another embodiment, a power supply is configured to supply power tothe bus bar, and a power storage system of the robot accessor isconfigured to receive power via the bus bar relay when it engages thebus bar. Thus both communications and power may be provided via the busbar and bus bar relay.

In a further embodiment, the robot control is configured to determine ifthe bus bar relay engages the bus bar and, if so, to signal theengagement via the accessor communication interface, e.g. so the powersupply may be activated.

In another embodiment, a computer program product is configured tooperate a programmable computer processor of a robot accessor of anautomated data storage library, and comprises computer program codeconfigured to operate the programmable computer processor to operate adrive system to move the robot accessor, to operate a bus bar relay toengage a bus bar of the automated data storage library when the robotaccessor is stationary, and to disengage the bus bar of the automateddata storage library when the robot accessor is moving; and to operatean accessor communication interface to provide communication capabilityover the bus bar relay and the bus bar when the bus bar relay engagesthe bus bar.

In a further embodiment, the computer program product computer programcode is configured to operate the programmable computer processor tooperate a second communication system of the robot accessor at leastwhen the robot accessor is moving.

In another embodiment, the computer program product computer programcode is configured to operate the programmable computer processor tooperate the second communication system in a low bandwidth mode ascompared to communication bandwidth of the accessor interface.

In still another embodiment, the computer program product computerprogram code is configured to operate the programmable computerprocessor to stop the robot accessor if, while the bus bar relay isdisengaged, communication of the second communication system is lost fora predetermined threshold.

For a fuller understanding of the present invention, reference should bemade to the following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric illustration of an automated data storage libraryemploying an embodiment of the present invention;

FIGS. 2A and 2B are diagrammatic illustrations of an embodiment of a busbar relay of the automated data storage library of FIG. 1 respectivelyengaging and disengaging a bus bar in accordance with the presentinvention;

FIG. 3 is a block diagrammatic illustration of an embodiment of thecommunications systems for the robot accessor in the automated datastorage library of FIG. 1;

FIG. 4 is a diagrammatic illustration of an optical communication systememployed in one embodiment of the present invention in thecommunications system of FIG. 3;

FIG. 5 is a diagrammatic illustration of a roller and bus communicationsystem employed in one embodiment of the present invention in thecommunications system of FIG. 3; and

FIG. 6 is a diagrammatic illustration of a brush and bus communicationsystem employed in one embodiment of the present invention in thecommunications system of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

This invention is described in preferred embodiments in the followingdescription with reference to the Figures, in which like numbersrepresent the same or similar elements. While this invention isdescribed in terms of the best mode for achieving this invention'sobjectives, it will be appreciated by those skilled in the art thatvariations may be accomplished in view of these teachings withoutdeviating from the spirit or scope of the invention.

Referring to FIG. 1, an automated data storage library 10 is configuredin accordance with an embodiment of the present invention with a robotaccessor 18 to access data storage cartridges stored in a plurality ofstorage shelves 16. The library 10 also comprises one or more datastorage drives 15 which read and/or write data with respect to the datastorage cartridges. As one example, the data storage cartridges maycomprise magnetic tape cartridges, and the data storage drives 15 maycomprise magnetic tape drives. Other types of removable media drives andcartridges may comprise magnetic media, such as hard disks, floppydisks, or any other type of magnetic media as is known to those of skillin the art. In addition, the removable media drives and cartridges maycomprise optical media such as CD (Compact Disk), DVD (Digital VersatileDisk), optical tape, or any other optical media as is known to those ofskill in the art. Still further, the removable media drives andcartridges may comprise electronic media such as CF (CompactFlash), SD(Secure Digital), xD (xD-Picture), Memory Stick, MMC (MultiMedia Card),MEMS (Micro-ElectroMechanical Systems) based storage, MRAM(Magnetoresistive Random Access Memory) or any other electronic media asis known to those of skill in the art.

The robot accessor 18 comprises a picker 20 configured to access anddeliver data storage cartridges to and from the storage shelves 16 andthe data storage drive(s) 15, and a drive system configured to move therobot accessor and to position the picker, at least such that the pickermay be positioned to access and deliver the data storage cartridge(s).In the illustrated example, the drive system comprises a carriage 24guided on a lower track 26 and on an upper track to move the carriage,and, hence picker 20, horizontally. The picker 20 is movable in thevertical direction to access the storage shelves and data storagedrives.

An accessor sensor 22, such as an LED (Light Emitting Diode)emitter/detector, a bar code scanner, camera, and/or other type ofreading system, such as a smart card reader, RFID (Radio FrequencyIdentification), or similar system, may be mounted on the picker 20, to“read” identifying information about the data storage cartridges.

The automated data storage library 10 may also comprise one or moreoperator panels 23 or other user interface, such as a web-basedinterface, which allows a user to interact with the library.

The automated data storage library may further comprise additionalframes, and the track 26 may continue into the additional frames. Inaddition, the library may also comprise a second robot accessor, similarto the robot accessor 18. In one example, in the event of a failure orother unavailability of the robot accessor 18, or its picker 20, etc.,the second robot accessor takes over.

An example of a data storage library which may implement the presentinvention is the IBM® 3584 UltraScalable® Tape Library.

Referring additionally to FIGS. 2A, 2B and 3, the robot accessor 18 isprovided with a bus bar relay 27 to provide burst communications whenthe robot accessor is stationary. Herein, a “stationary” robot accessorrefers to motion as it relates to the bus bar 28, 29 of FIGS. 1, 2 and3. In addition, “stationary” may refer to some amount of motion in thatthe accessor motion may be decelerating during engagement of the bus barrelay and may be accelerating during disengagement of the bus bar relay.The robot accessor may be stationary when there are no host commands toprocess. In one embodiment, host commands are received by one or morelibrary controllers and then the commands are either forwarded to therobot accessor, or other commands or signals are sent to the robotaccessor to provide the necessary cartridge movement. In addition, therobot accessor may be stationary during a cartridge put or get operationto/from a data storage drive 15 or to/from a storage slot. The robotaccessor may need to be stationary during these actions to preventdamage to components of the accessor. Still further, the robot accessormay be stationary due to a failure of the robot accessor, or if therobot accessor runs out of power, as will be discussed. The bus barrelay 27 is configured to engage and disengage a bus bar 28, 29 of thelibrary. The bus bar 28 may comprise any suitable material for carryingcommunication signals and is arranged generally parallel to thedirection of motion of the robot accessor. In the illustratedembodiment, the bus bar 28 comprises a communication connection, and busbar 29 is grounded 32. Alternatively, rather than grounding bus bar 29,bus bar 28, 29 may comprise a differential communication pair. Stillfurther, there may be only one half 28 of bus bar 28, 29 and the groundconnection may be provided through the contact of other metal parts ofthe library/accessor system. Still further, there may be more than twoconnections. In this case, additional connections may be provided forredundancy, for multiple communication channels, etc. Herein, “bus bar”refers to a temporary contact point for providing communication to anaccessor, and “bus bar relay” refers to a mechanism for providing thetemporary contact to the bus bar.

The automated data storage library 10 is part of a data storage systemin which commands and data are provided from one or more hosts 31 viaone or more external interfaces 32, and the library executes thecommands and provides responses and requested data to the hosts 31. Ahost 31 may comprise a computer, workstation, server, virtual tapesystem, control unit, storage server, a storage control, a networkedsystem, etc., as is known to those of skill in the art.

A robot control 33 may comprise a computer system, one or moreprocessors, part or all of a distributed control system, FPGA (FieldProgrammable Gate Array), ASIC (Application Specific IntegratedCircuit), discrete logic, or any other method of control as is known tothose of skill in the art. A robot control 33, in one embodiment,comprises a memory 34 to store the computer program code of a computerprogram product to cause the programmable computer system, processor,FPGA, ASIC or other programmable logic to provide the desired operationsof the robot accessor 18. The memory 34 may be integrated into acomputer system, processor, FPGA, ASIC, or other device or system.Alternatively, the memory 34 may be a discrete memory or storagecomponent. The memory may comprise electronic storage such asprogrammable logic, RAM (Random Access Memory), PROM (Programmable ReadOnly Memory), EEPROM (Electrically Erasable PROM), flash PROM, MRAM(Magnetoresistive RAM). Alternatively, the memory may comprise magneticstorage such as a hard disk drive, floppy drive, magnetic tape, etc. Inaddition, the memory may comprise optical storage such as an opticaldisk drive, optical tape, etc. Still further, the memory may compriseany memory or storage technology as is known to those of skill in theart. The computer program product may be supplied to the robot control33, for example, by means of the operator interface 23 or a web userinterface. The computer program product may also be provided from someother user or remote interface, a network, host computer, libraryservice port, through a wireless connection, or by a diskette, DVD(Digital Versatile Disk), memory card, or compact-disk “CD”, or anyother method of providing a computer program product, as is known tothose of skill in the art.

The robot control 33 is configured to operate the drive system, e.g.carriage 24, to move the robot accessor 18, and may operate the picker20.

In accordance with an embodiment of the present invention, the robotcontrol 33 is configured to operate the bus bar relay 27, eitherdirectly or indirectly, to engage the bus bar 28, 29 when the robotaccessor is stationary, and to disengage the bus bar 28, 29 when therobot accessor is being moved. In a preferred embodiment, the bus barrelay 27 engages the bus bar 28, 29 when there is no power present onrobot accessor 18, or the robot accessor stops due to a malfunction.

Referring to FIGS. 2A and 2B, the bus bar relay 27, in one embodiment,comprises a pair of single pole single throw relays, comprisingactuators 35 and 36 which operate communication arms 37 and 38 to moverelay contacts 39 and 40 into engagement with the bus bar 28, 29, and todisengage the relay contacts. The bus bar 28, 29 may be supported byframe support 41, and communication bar 28 is insulated from the framesupport.

In an alternative embodiment, the bus bar relay 27 may comprise multiplepole single throw contacts. Further, the bus bar relay 27 may compriseredundant relay elements to guard against single relay failure. Stillfurther, the contacts may be sufficiently durable, for example, hardenedcontacts, so as to tolerate motion in contact with the bus bar 28, 29 toallow for electrical contact during acceleration and deceleration of theaccessor 18, or in the event of a failure of actuators 35 and 36 or forlong enough to allow the robot accessor to be moved out of the way alongthe rails for repair. In one embodiment, the actuators 35 and 36 areoperated electrically in a similar way that a relay is actuatedelectrically. In another embodiment, the actuators 35 and 36 areoperated through a mechanical link to the accessor drive or rail system.When the accessor 18 begins to move, the communication arms 37, 38 aremechanically driven away from the bus bar 28, 29.

Referring to FIGS. 2A, 2B and 3, the robot accessor 18 comprises anaccessor communication interface 43. Wires 46 and 47 may provide adirect communication link between the relay contacts 39 and 40 and theaccessor communication interface 43. The wires 46 and 47 may be arrangedto minimize the flexing of the wires to prolong their durability andreliability.

The robot control 33 is configured to operate the accessor communicationinterface 43 to provide communication capability with a librarycommunication interface 48 via the bus bar relay 27 and the bus bar 28,29 when the bus bar relay 27 engages the bus bar 28, 29.

A library controller 50, which may comprise one or more processors, maybe in communication with the library communication interface 48, and,when the communication capability is provided by the accessorcommunication interface 43 and bus bar relay 27, the library controller50 and the robot accessor 18 communicate in burst mode, for example, thelibrary controller providing commands or signals to the robot control 33to make desired moves, or providing address information so that a robotcontrol 33 of the robot 18 can determine the desired moves.Additionally, the robot control 33 may provide information from thesensor 22 of FIG. 1 mounted on the robot accessor or picker, such asinformation read from the shelves, markers within the library, and/orfrom labels of the data storage cartridges, and communicate theinformation to the library controller 50. The accessor communicationinterface 43 and the library communication interface 48 may comprise aserial interface such as RS-232 (Recommended Standard), RS-422, CAN(Controller Area Network), USB (Universal Serial Bus), IEEE 1394,Ethernet, etc. Alternatively, the accessor communication interface 43and the library communication interface 48 may comprise a parallelinterface such as SCSI, IEEE 1284, etc. Still further, any commercial orproprietary communication interfaces may be use, as is known to those ofskill in the art.

Herein, “communication capability” comprises any suitable operationwhich provides the ability to communicate via digital and/or analogsignaling.

Referring to FIGS. 1, 2A, 2B and 3, in a further embodiment, theautomated data storage library additionally comprises a secondcommunication system 30, 53 between the robot accessor 18 and theautomated data storage library, the second communication system operableat least when the robot accessor is moving.

The bus bar relay 27 is disengaged when the robot accessor 18 is moving,such that there is only burst communication when the robot accessor isstationary. The second communication system 30, 53 may therefore servein a low bandwidth communication mode as compared to the communicationbandwidth of the accessor interface 43, so as to be effective in apotentially high noise environment. The low bandwidth signaling may beas simple as a binary “on-off” coding, or more complicated coding ormodulated signaling, and may comprise error correction techniques. Anexample of the signaling is that a constantly “on” signal from the robotaccessor 18 indicates that the robot accessor is operating correctly,and/or moving, and an absence of a signal means that the robot accessoris experiencing trouble and/or is stopped. An example of signaling fromthe library to the robot accessor may be constantly “on” to indicatethat the library is operating normally, and an absence of a signal meansthat power is about to go off. In one embodiment, the signaling from thelibrary to the robot is used to indicate that it may not be safe for therobot to continue in motion. For example, a library access door 49 ofFIG. 1 may have been opened and continued robot motion may comprise asafety hazard for the person opening the library access door. In thisexample, the robot ceases any motion when the signaling from the libraryto the robot indicated that a library access door may have been opened.A library access door may comprise a door, hatch, cover, panel,magazine, or any other structure or assembly that may provide access toany portion of the library that is not normally accessible. Because ofthe possible noise, a threshold time period may be established for anabsence of a signal to be registered by the receiver. Alternatively, athreshold in a coding or modulated signaling system may comprise aduplication of the signaling codes, or a special “attention” codesequence may be utilized, as is known to those of skill in the art.

Referring to FIGS. 1 and 3, in a further embodiment of the presentinvention, the robot control 33 is additionally configured to stop therobot accessor 18 if, while the bus bar relay 27 is disenganged,communication of the second communication system is lost for apredetermined threshold, the thresholds discussed above.

The example of a secondary communication system 30, 53 illustrated inFIGS. 1 and 3 comprises an RF (radio frequency) communication system, asis known to those of skill in the art.

FIG. 4 illustrates an alternative secondary communication systemcomprising an optical communication system 55, 57, having an opticalsource 58, 59, and an optical receiver 60, 61 at either side of thecommunication link, specifically at the robot accessor 18 and at thelibrary communication interface 53. The optical sources and receiversmay comprise LEDs and optical detectors, and the LEDs may be providedthroughout the library to provide communication with the robot accessorat all points in the library. Alternatively, the optical sources maycomprise lasers. It should be noted that there may not be a need for tworeceivers 60, 61 and/or two transmitters or sources 58, 59. This may bethe case if there is only a need to determine library status or accessorstatus, and not both. In addition, there may not be a need for asecondary communication system at all. This may be the case if there areno safety concerns with a given library design. Still further, at therobot accessor 18, the accessor sensor 22 may also serve as the opticalcommunication system 30. Further optical communication systems are alsoknown to those of skill in the art.

Thus, the potentially noisy or intermittent nature of communicationthrough RF or optical communications still is useable in the lowbandwidth communication environment.

FIG. 5 illustrates a further secondary communication system comprising aroller and bus communication system 67, 68 employing rollers 70 and 71of robot accessor 18 to contact the bus 28 and ground 29, or a similarbus system, and to provide a low bandwidth communication, as discussedabove, with respect to the library. Herein, such a system is termed a“bus bar contact”. The roller and bus communication system 67, 68 is notwell suited for high bandwidth communication during motion because theroller may induce noise, intermittent connections, etc. However, if highbandwidth communication is limited to periods where accessor motion isstopped, the roller and bus communication system 67, 68 may be used asthe primary burst communication instead of the bus bar relay. In oneembodiment, the roller and bus communication system 67, 68 actuallyprovides the high bandwidth communication when the accessor is stopped.In a variation of this embodiment, a secondary communication system isused when the accessor is moving.

FIG. 6 illustrates a further secondary communication system comprising abrush and bus communication system 75, 76 employing brushes 78 and 79 ofrobot accessor 18 to contact the bus 28 and ground 29, or a similar bussystem, and to provide a low bandwidth communication, as discussedabove, with respect to the library. Such a system is also termed a “busbar contact”. The brush and bus communication system 75, 76 is not wellsuited for high bandwidth communication during motion because the brushmay induce noise, intermittent connections, etc. However, if highbandwidth communication is limited to periods where accessor motion isstopped, the brush and bus communication system 75, 76 may be used asthe primary burst communication instead of the bus bar relay. In oneembodiment, the brush and bus communication system 75, 76 actuallyprovides the high bandwidth communication when the accessor is stopped.In a variation of this embodiment, a secondary communication system isused when the accessor is moving.

Thus, the intermittent nature of communication through rollers orbrushes or similar bus bar contacts still is useable in the lowbandwidth communication environment, and may even be used for highbandwidth communication when there is no motion.

Referring to FIGS. 2 and 3, a power supply 44 of the library may supplypower (AC and/or DC) to the bus bar 28, 29. The power supply 44comprises any suitable power supply as is known to those of skill in theart. A power storage system 45 is configured to receive power via thebus bar relay 27 when the bus bar relay engages the bus bar 28, 29. Thecommunication signal may be modulated on the power signal.Alternatively, the communication signal may be capacitively coupled tothe power signal. Still further, any method of combining power andcommunication signals may be used as is known to those of skill in theart.

Thus, both power and communications may be provided via the bus bar 28,29 and the bus bar relay 27 when the robot accessor is stationary andthe bus bar relay engages the bus bar. Alternatively, there may beseparate arms 37, 38 and/or separate contacts 39, 40 and/or separate busbars 28, 29 for communication and power.

The power storage system 45 may comprise a battery system, a capacitorsystem, and/or super-capacitor to store power, which systems are knownto those of skill in the art. The power storage system 45 is arranged toreceive power from the power supply 44 via the bus bar engaged bus barrelay, for example, by a direct connection to the relay contacts 39 and40 via wires or cables 80 and 81 of FIGS. 2A and 2B. As discussed above,optionally, the bus bar may comprise one half 28 of the bus bar, and theground connection may be provided through the contact of other metalparts.

The power supply system 45 stores the received power and may deliver thestored power to the picker 20, the drive system, the accessorcommunication interface 43, the bus bar relay 27, the robot control 33,34, to any secondary communication system 30, and to any accessor sensor22 of FIG. 1, if needed. Some or all of the components of the robotaccessor 18 may receive power directly from the bus bar relay 27 or thebus bar contacts (FIGS. 5 and 6) when the robot accessor is stationary.In this case, the power supply system 45 may not be supplying any powerwhile it is charging. Alternatively, the components of the robotaccessor may always receive power from the power supply system 45, evenwhen the accessor is stopped. In this case, the power supply system 45may be charging at the same time that is supplying power. The power issupplied at the desired voltages and current capacities and of thedesired type (e.g. AC and/or DC), as is known to those of skill in theart.

The robot control 33 of FIG. 3 may additionally be configured todetermine if the bus bar relay 27 engages the bus bar 28, 29. Forexample, a detector 83 may sense the operation of the actuators 35, 36of FIGS. 2A and 2B, for example, by current flow, inductance, etc.; maysense the position of arms 37, 38, for example, by a micro switch; ormay sense the completion of the circuit, for example, by voltage orsignal. Examples of such detectors are known to those of skill in theart.

The robot control senses the condition of the detector 83 and, if thebus bar relay engages the bus bar, provides a signal via the accessorcommunication interface 43, the bus bar relay 27, and the bus bar 28, 29to indicate that the bus bar relay has engaged the bus bar. The librarycontrol 50 may receive and respond to the signal by activating the powersupply 44. Thus, power may be supplied only when the robot accessor 18is stationary. The robot control 33 may also provide a signal toindicate that the bus bar relay 27 is to be operated to disengage thebus bar 28, 29. The library control 50 may thus deactivate the powersupply prior to the disengagement and avoid surges to the system. Thismay limit the amount of pitting that may occur on the contacts and busbar due to arcing or sparking and thereby improve bus bar relay contactlife and/or bus bar life. Alternatively, robot control 33 and librarycontrol 50 may determine that the bus bar relay 27 has engaged the busbar 28, 29 by the fact that communication has been established on thebus bar, not requiring a detector 83. A time delay and/or acommunication signal between the robot control 33 and the librarycontrol 50 may be used by library control 50 as an indication that itcan activate power to the bus bar. A communication signal between therobot control 33 and the library control 50 may also be used to indicatethat power should be removed from the bus bar because the robot accessor18 is about to move. Alternatively, since movement of the robot accessoris typically related to host or library commands, library control 50 mayremove power from the bus bar prior to sending any commands or signalsto robot control 33 that may result in robot accessor motion. Theseapproaches may require that the robot accessor 18 has power to beginwith. If the robot accessor 18 has run out of power, the library control50, or some other circuit coupled to the bus bar, may provide adetection method to allow the library control 50, or other circuit, todetermine that the bus bar relay 27 has made contact with the bus bar.Examples of how library control 50, or some other circuit, may determinethat bus bar relay 27 has made contact with the bus bar may comprise,measuring the impedance of the bus bar circuit, determining that anelectrical load has been placed on the bus bar, determining that one ormore circuits have been closed, etc. One skilled in the art willrecognize that these methods may be employed with power circuits that donot require any actual involvement of library control 50. Time delaysmay be employed to ensure that the contacts are not bouncing or inpartial contact when power is applied to, or removed from, the bus bar.Herein, activating a power supply may comprise turning power on, or itmay comprise an increase in voltage and/or current output of the powersupply. Deactivating a power supply may comprise turning the powersupply off, or it may comprise a decrease in voltage and/or currentoutput of the power supply.

Those of skill in the art will understand that differing specificcomponent arrangements may be employed than those illustrated herein.

While the preferred embodiments of the present invention have beenillustrated in detail, it should be apparent that modifications andadaptations to those embodiments may occur to one skilled in the artwithout departing from the scope of the present invention as set forthin the following claims.

1. An automated data storage library, comprising: a plurality of storageshelves configured to store data storage cartridges; at least one datastorage drive configured to read and/or write data with respect to saiddata storage cartridges; a bus bar; a library communication interfaceconfigured to communicate with said bus bar; and a robot accessorcomprising: a picker configured to access and deliver at least one saiddata storage cartridge to and from said storage shelves and said atleast one data storage drive; a drive system configured to move saidrobot accessor and to position said picker, at least such that saidpicker may be positioned to access and deliver said at least one datastorage cartridge; an accessor communication interface; a bus bar relayconfigured to engage and disengage said bus bar; and a robot controlconfigured to operate said drive system to move said robot accessor, tooperate said picker to access and deliver said at least one data storagecartridge, to operate said bus bar relay to engage said bus bar whensaid robot accessor is stationary, and to operate said accessorcommunication interface to provide communication capability with saidlibrary communication interface via said bus bar relay and said bus barwhen said bus bar relay engages said bus bar.
 2. The automated datastorage library of claim 1, additionally comprising a secondcommunication system between said robot accessor and said automated datastorage library, said second communication system operable at least whensaid robot accessor is moving.
 3. The automated data storage library ofclaim 2, wherein said second communication system is a low bandwidthcommunication system as compared to communication bandwidth between saidaccessor communication interface and said library communicationinterface via said bus bar relay and said bus bar.
 4. The automated datastorage library of claim 2, wherein said second communication systemcomprises an optical communication system.
 5. The automated data storagelibrary of claim 2, wherein said second communication system comprisesan RF communication system.
 6. The automated data storage library ofclaim 2, wherein said second communication system comprises a roller andbus communication system.
 7. The automated data storage library of claim2, wherein said second communication system comprises a brush and buscommunication system.
 8. The automated data storage library of claim 2,wherein said robot control is additionally configured to stop said robotaccessor if, while said bus bar relay is disengaged, communication ofsaid second communication system is lost for a predetermined threshold.9. The automated data storage library of claim 2, wherein said robotcontrol is additionally configured to stop said robot accessor if, whilesaid bus bar relay is disengaged, said second communication systemindicates that a library access door is opened.
 10. The automated datastorage library of claim 1, additionally comprising a power supplyconfigured to supply power to said bus bar; and wherein said robotaccessor additionally comprises a power storage system configured toreceive power via said bus bar relay when said bus bar relay engagessaid bus bar, to store said received power, and to deliver said storedpower to said robot accessor at least when said bus bar relay isdisengaged.
 11. The automated data storage library of claim 10, whereinsaid robot control is configured to determine if said bus bar relayengages said bus bar and, if so, to signal said engagement via saidaccessor communication interface, whereby said power supply may beactivated.
 12. The automated data storage library claim 10, wherein saidautomated data storage library is configured to determine if said busbar relay engages said bus bar and, if so, to activate said powersupply.
 13. The automated data storage library claim 10, wherein saidautomated data storage library deactivates said power supply prior tosending any commands or signals to said robot accessor that may resultin robot accessor motion.
 14. A robot communication system configuredfor a robot accessor of an automated data storage library, said robotaccessor having a drive system to move said robot accessor, saidautomated data storage library having a bus bar, said robotcommunication system comprising: an accessor communication interface; abus bar relay configured to engage and disengage said bus bar; and arobot control configured to operate said drive system to move said robotaccessor, to operate said bus bar relay to engage said bus bar when saidrobot accessor is stationary, and to operate said accessor communicationinterface to provide communication capability over said bus bar relayand said bus bar when said bus bar relay engages said bus bar.
 15. Therobot communication system of claim 14, additionally comprising a secondcommunication system of said robot accessor, said second communicationsystem operable at least when said robot accessor is moving.
 16. Therobot communication system of claim 15, wherein said secondcommunication system is a low bandwidth communication system as comparedto communication bandwidth of said accessor interface.
 17. The robotcommunication system of claim 15, wherein said second communicationsystem comprises an optical communication system.
 18. The robotcommunication system of claim 15, wherein said second communicationsystem comprises an RF communication system.
 19. The robot communicationsystem of claim 15, wherein said second communication system comprises aroller communication system configured to operate with a bus of saidautomated data storage library.
 20. The robot communication system ofclaim 15, wherein said second communication system comprises a brushcommunication system configured to operate with a bus of said automateddata storage library.
 21. The robot communication system of claim 15,wherein said robot control is additionally configured to stop said robotaccessor if, while said bus bar relay is disengaged, communication ofsaid second communication system is lost for a predetermined threshold.22. The robot communication system of claim 15, wherein said robotcontrol is additionally configured to stop said robot accessor if, whilesaid bus bar relay is disengaged, said second communication systemindicates that a library access door is opened.
 23. The robotcommunication system of claim 14, additionally comprising a powerstorage system configured to receive power via said bus bar relay whensaid bus bar relay engages said bus bar, to store said received power,and to deliver said stored power to said robot accessor at least whensaid bus bar relay is disengaged.
 24. The robot communication system ofclaim 23, wherein said robot control is configured to determine if saidbus bar relay engages said bus bar and, if so, to signal said engagementvia said accessor communication interface, whereby said power supply maybe activated.
 25. A data storage system comprising: at least one host;and an automated data storage library, comprising: a plurality ofstorage shelves configured to store data storage cartridges; at leastone data storage drive configured to read and/or write data with respectto said data storage cartridges; at least one external interfaceconfigured to communicate with said at least one host; a bus bar; alibrary communication interface configured to communicate with said busbar; and a robot accessor comprising: a picker configured to access anddeliver at least one said data storage cartridge to and from saidstorage shelves and said at least one data storage drive; a drive systemconfigured to move said robot accessor and to position said picker, atleast such that said picker may be positioned to access and deliver saidat least one data storage cartridge; an accessor communicationinterface; a bus bar relay configured to engage and disengage said busbar; and a robot control configured to operate said drive system to movesaid robot accessor, to operate said picker to access and deliver saidat least one data storage cartridge, to operate said bus bar relay toengage said bus bar when said robot accessor is stationary, and tooperate said accessor communication interface to provide communicationcapability with said library communication interface via said bus barrelay and said bus bar when said bus bar relay engages said bus bar.